1. Field of Invention
This invention pertains to the art of methods and apparatuses for use in lawn and garden care, and more specifically to methods and apparatuses for controlling the speed and direction of a zero turn lawn tractor.
2. Description of the Related Art
It is well known to provide lawn tractors having direction control such as a steering wheel and speed control such as a throttle pedal or lever. A relatively recent improvement is lawn tractors having zero radius turning capabilities. They are commonly referred to as zero turn tractors. A zero turn tractor may have two drive wheels, one on each side of the tractor, and two independent control levers. Each control lever controls the speed and the direction of one of the drive wheels. To make a zero radius turn it is necessary to drive one of the drive wheels in a first or forward direction while simultaneously driving the other drive wheel in a second or reverse direction. Such zero turn tractors have proven to be adequate for their intended purpose. Some problems, however, have been experienced.
One problem is called turfing. Turfing is the damage done to the ground or turf when an operator too abruptly turns a zero turn tractor. Operators have a tendency when turning a zero turn tractor to "turn" the control levers much like a steering wheel is turned. In other words, operators have a tendency to pull one control handle backwards while pushing the other control handle forward. This pull/push motion may cause the inside drive wheel to slide across the turf thereby damaging the turf. What is needed is a way to minimize turfing.
Another problem relates to the ergonomics of controlling a lawn tractor. Steering wheels of known lawn tractors actually provide at least two functions for the operator. One function is the steering control. The second function is that the steering wheel provides a resting surface to rest the operator's hands. For lawn tractors that do not have a steering wheel but rather have control levers, however, the operator's hands may not be rested on such control levers without the lawn tractor's speed and/or direction being inadvertently adjusted. Therefore, the operator's hands must be supported by the operator's arms and shoulders. This may prove to be tiring for the operator's arms, shoulders and back when the lawn tractor is driven for large amounts of time. What is needed is a way of utilizing independent control levers while still providing a means for resting the operators hands and thus his arms, shoulders and back.
Another problem is that known zero turn lawn tractors do not permit the limiting of the top speed below the limits of the lawn tractor itself. In other words, only by maintaining the operator's hands at specific positions with respect to the control levers can the zero turn lawn tractor be maintained at a predetermined top speed. What is needed is a simple way for the operator to maintain the lawn tractor at a given top speed.
The present invention provides methods and apparatuses for reducing these problems. The difficulties inherent in the art are therefore overcome in a way that is simple and efficient while providing better and more advantageous overall results.